Moire microscope

Abstract

A moire microscope comprises an objective lens, a collimating lens, and a pair of spaced-apart gratings arrayed along an optic axis and adapted for providing a magnified moire deflectogram of a phase object. The microscope provides a simple apparatus for preparing a map of optical thickness gradients, from which quantitative data concerning the object can be computed.

We claim: 
     
       1. An apparatus for moire microscopy comprising, in combination and spaced apart successively along an optic axis, (a) an objective lens for focusing a light beam from an object,   (b) a collimating lens, for collimating the beam from the objective lens, and   (c) two spaced-apart gratings for producing from the collimated beam a magnified moire deflectogram of the object.   
     
     
       2. The apparatus of claim 1 in which rulings on one of the gratings are parallel to rulings on the other grating. 
     
     
       3. The apparatus of claim 1 in which one of the gratings is mounted so that it is rotatable about an axis that substantially coincides with the optic axis. 
     
     
       4. The apparatus of claim 1 further comprising means for making visible the deflectogram of the object. 
     
     
       5. The apparatus of claim 4 in which the means for making the deflectogram visible is a matte screen. 
     
     
       6. The apparatus of claim 4 in which the means for making the deflectogram visible includes a photosensitive material. 
     
     
       7. The apparatus of claim 1 further comprising a beam splitter between the collimating lens and the gratings.